Re: [PATCH v2 1/2] x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area.

[Dave Hansen]

On 9/24/19 1:04 PM, Steve Wahl wrote:
> Given that, would you feel better with A) the way I have it, B) your
> rewrite, or C) with an inline comment for each part of the loop:
> 
> 	pmd = fixup_pointer(level2_kernel_pgt, physaddr);
> 
> 	/* invalidate pages before the kernel image */
> 	for (i = 0; i < pmd_index((unsigned long)_text); i++)
> 		pmd[i] &= ~_PAGE_PRESENT;
> 
> 	/* fixup pages that are part of the kernel image */
> 	for (; i <= pmd_index((unsigned long)_end); i++)
> 		if (pmd[i] & _PAGE_PRESENT)
> 			pmd[i] += load_delta;
> 
> 	/* invalidate pages after the kernel image */
> 	for (; i < PTRS_PER_PMD; i++)
> 		pmd[i] &= ~_PAGE_PRESENT;

I don't feel super strongly either way, but I'd prefer doing B or C over
nothing.